The Supreme Court justices paid an average of $42,539 to go to college. Today, they'd have to pay around $320,531.

• The Supreme Court struck down Biden's student loan forgiveness plan.
• Student loan payments will likely resume in October.

The Supreme Court on Friday ruled that President Joe Biden's student loan forgiveness plan is illegal.

In a 6-3 opinion, the nation's highest court said the law the Biden administration planned to use to cancel school debt for some students was inappropriate. That leaves room for Biden to pursue other avenues to forgive student debt.

But, for now, students will likely have to start repaying their debt again in October.

Biden had announced plans to cancel up to $20,000 in student debt for federal borrowers making under $125,000 a year. Republicans have pushed back against the measure, and several lawsuits have tried to block it.

The court's ruling will impact the lives of millions of student loan borrowers, including the 20 million borrowers that the White House estimates would have their balances completely wiped out.

The cost of going to college or university has skyrocketed in recent decades, crippling many students entering the workforce who took out loans to pay for their education. According to historical tuition data, the price of college — for instance — has changed astronomically since the justices now sitting on the Supreme Court were in school.

Four of the nine justices graduated throughout the 1970s, a time when the average student loan debt was about $1,000, according to data from the research group The Education Data Initiative. By 2021, the average student debt at graduation was about $31,000, the group reported, citing federal data.

According to EDI, there was a 2,807% increase in the average student loan debt at graduation between 1970 and 2021 before adjusting for inflation. The debt was still a 317% increase after accounting for inflation.

The overall cost of college tuition and fees soared 1,200% since 1980, Insider previously reported. Adjusting for inflation the cost to attend a public university in the US at that time was just $1,856.

While each of the justices went on to get advanced law degrees, here's how much a four-year undergraduate degree at their elite, private alma maters would have cost when they graduated and what it would cost at those universities today:

• When Justice Clarence Thomas finished his undergraduate degree at The College of the Holy Cross in 1971, the estimated cost of attendance for four years was $14,550, according to a research memo from the progressive-leaning advocacy group Take Back the Court. Now, a four-year degree would cost $299,920.
• A four-year degree at Princeton University would now cost about $318,160 over four years. That degree only cost $15,040 when Justice Samuel Alito graduated in 1972. The cost of attendance was $21,900 in 1976 when Justice Sonia Sotomayor graduated and $41,055 when Justice Elena Kagan graduated in 1981.
• Justices John Roberts and Ketanji Brown Jackson both graduated from Harvard. The cost to attend the prestigious university is an estimated $337,652, according to Take Back the Court. When Roberts graduated in 1979, it cost $21,400; in 1992 when Jackson earned her undergraduate degree, it would have cost $75,360.
• When Justice Brett Kavanaugh graduated from Yale as an undergraduate in 1987, it would have cost an estimated $57,990. Now, four years at Yale would cost around $338,100, according to the memo. A year later, in 1988, Justice Neil Gorsuch would graduate from Columbia University, costing an estimated $64,900 for four years. Now that cost is around $343,868.
• In 1994, when Justice Amy Coney Barrett graduated from Rhodes College, the four-year cost of attendance would have been around $70,664. Today, four years would cost around $273,112.

While the cost of getting an undergraduate degree has increased since all nine justices graduated, several of them appear to understand the impact of rising tuition fees.

In his 2007 memoir, Thomas discussed the "crushing weight" of student debt that he was still paying off from his law school days when he was appointed to the bench.

Additionally, according to the justice's own financial disclosures, as well as reporting from The Associated Press, some of the justices have put aside large investments for their own children's college funds. Four of the seven justices who have children have invested in tax-free college savings accounts for their children. The AP reported that Roberts had at least $600,000 invested in an account for his two children, while Gorsuch has at least $300,000.